While preventive efforts to reduce spread of HIV infection have been somewhat effective in reducing risky behaviors in homosexuals, similar efforts to reduce needle sharing and high risk sexual activity in IV drug abusers and their sexual partners have not yet been demonstrated to be effective. Two target populations that have been particularly hard to reach have been (a) IV drug abusers who are not in treatment and (b) regular sexual partners of IVDUs. To provide data on (1) the most effective settings for outreach interventions and (2) the most effective intensity of interventions at each setting, three simultaneous outreach trials will be conducted for these two target populations. Across the three settings the core intervention offered by outreach workers and the assessments of intervention effectiveness will be standardized. Six month follow-up interviews will determine change both across and within settings for three major outcomes: education, behavioral risk reduction, and treatment/service utilization. The three settings are as follows: (1) the community/street level, where the interventions will consist of (a) Assessment/Service Coordination/Education by indigenous outreach workers offered through i. door-to-door canvassing of high risk neighborhoods and ii. networking with community groups and/or drug-using contacts in order to reach IVDUs alone and in combination with (b) Assessment/Service Coordination/Education efforts by medically trained personnel offered from a mobile van which will be stationed in high risk communities. (2) An institutional level, where individuals in the target populations will be identified at three settings: hospital emergency rooms, welfare offices, and probation offices. At each of these settings the intervention to be offered will be (a) the provision of single contact Assessment/Service Coordination/Education session with on-site caseworkers alone or in combination with (b) more intensive, individualized follow-up counseling. (3) A Central Project Headquarters/Storefront, where the interventions to be offered will be a package of (a) ongoing Assessment/Service Coordination/Education by a case manager, a free medical evaluation and referral, and HIV testing. This intervention package will be offered alone or in combination with (b) a course of risk reduction skills training.